Try this:

Private Sub neworderbtn_Click()

Docmd.openform "OrderF", , , "CustomerID=" & CustomerID, acFormAdd

End Sub

It's asking for macro info when I run it.

What is Access asking? What Info?

At first it was opening a window asking for a macro, looking in the file that I've created.
Now it give me an error. After clicking on it I get the following error:
Run time error 2105
You can't go to the specified records

the debuuger then highlights my second line of code.

And, I've tried the code that you created, narrowing it down to one line. A new order does open, but not with the client ID of the client that's open.

For the form you are opening to get the ClientID you need to set a Default Value

Thank you for the default value recommendation. I set clientid and customername to the value of the same fields in customerF, then created a macro to open the form with data mode set to add. And it works great.
I'm just wondering why I couldn't do it through code? Richard created a video to do just that, with the same forms, tables, and fields that I'm working with. That's strange.
I did take some notes of what it was doing when I was trying to get the code working. And this is what it was doing with Sami's code suggestion, when I entered it and ran the debug.
I would get a window that appeared. It looked like it wanted me to choose a macro. But there weren't any macros in the window that appeared. The window that appeared was as follows:
Macro Name:
(empty box under that)
(empty window under that)
cmd  buttons to the right of these boxes
run (grayed out)
cancel
step into (grayed out)
edit (grayed out)
create (grayed out)
delete (grayed out)

Perhaps the Button still had the Macro attached. Without seeing it I couldn't really tell you.
Try adding a new Button (cancel the wizard). Add the code to the Click event of this Button.

That's a great suggestion. I just tried that. Same result. I tried it, same result.
Then I created a brand new DB with two tables, two forms. It took a little work, but I got it working. So there's something up with the database that I'm working off of.
That's good to learn. Thanks for getting me there. I'm going to see if I can find the culprit.